Rotary magnet



June 17, 193. l 1 STQECKUN 1,764,658

' ROTARY MAGNET iled Aug. 23, 1928 Patented June 17, 1930 UNITED STATES JOSEF STOECKLIN, OF ZURICH, SWITZERLAND, ASSIGNOR TO AKTIENGESELLSCHAFT- BADEN, SWITZERLAND, A JOINT-STOCK COMPANY 'OF BROWN BOVERI & CIE., OF SWITZERLAND l PATENT OFFICE ROTARY MAGNET .Application led August 23, 1928, Serial No.

This invention relates to electro-magnets, and v more particularly to electrofmagnets having a rotating armature, such for instance, as are generally employed in the remote operation and control of switches, regullating resistances, fluid valves, indicating devices, and for various otherpurposes.

The 'armature of a magnet of this type assumes various positions in accord with the changing magnetic flux in the excited porltions of the armature and the change in polarity produced by change in the idirection of the flow of current in the exciting coil.

The armatures of such magnets, however, have not been suiciently positive and exact in operation to permit their use for purposes Where' only a small operating angle 1s required, due to the lack of uniformity of' torque thereof.

It is, therefore, among the objects of my present invention to provide a rotating armature magnet in which a high degree of exactness is obtained.

Another object of the invention is to provide a` rotating armature magnet having a relatively high torque in spite of operation at a small angle. Y

Other objects and advantages will appear in the following description and the 'draw- 3o ings, in which,`for purposes of illustration only, several embodiments of the invention are shown, and wherein Figure 1 is'a vertical cross sectional View of the invention' taken on approximately the central line therethrough. y

Figure 2 is a vertical cross sectional view of the invention taken on the line 4A-A of Fig. 1.

Fig. 3 is a partial sectional view similar to Fig. 2 but showing only the armature and the pole shoes with the armature shown'in the extreme position in dotted lines.

-Fig. 4 is a curve showing the torque of the armature plotted against the angle of operation.

Fig. 5 is a view of a modification of the invention similar to Fig. l butshowing a magnetic 'means for replacing a portion'of the ymechanical Astructure hereinafter described with relation to Fig. 1.

301,465, and in Germany October 25, 1927.

Fig. 6 is a View si'milar to Fig. 2, taken on the line B-B of Fig. 5.

Referring more particularlyto .the drawing by characters of reference, 10 indicates a cylindrical magnetically permeable metallic housing within which is arranged a cylindrical coil 11. The'coil 11 is adapted to be connected with an electrical circuit in the usual manner for the coils of electro-mag- `in the coil with respect to the longitudinal as well as the lateral axis, and are oppositely arranged in pairs,'each pole shoe of the respective pairs when energized being a north or` a south pole, dependent on the direction of the flow o current within the coil.

A spacing member 18, formed of non-mag netic materlal, is secured to the shaft, and has mounted thereon, at the ends away from the shaft, a pair of armature shoes 19 and 20, which are formed from suitable magnetic materials. The shaft 17 is supported in suitable trunnions or bearings 21, disposed eXte-V riorly of the housing 1() at the ends thereof.

It will be seen from the 'drawing that the armature shoes 19 and 20 magnetically bridge the air gap between the pole shoes 13, 14, 15 and 16, thereby completing the magnet circuit for the field produced by the coil. The armature shoes 19 ,and 20 are narrower than the air gap between the respective pairs of pole shoes. Astop 21 is connected to one of the bearings for the shaft 17 to limit the rotation of the armature member. J The armavor any other suitable device for biasing the armature. Rotation of the, armature against the stop retains .thel armature in the position in whichl maximumvtorque may be obtained immediately upon excitation of the magnet-- izing coil.

In operatlon of the electro-magnet, the cn'- I cuit through the coil 11 is closed, thereby cxtion, of course, takes place between the pole shoes 15 and 16', which action, co-operating with the field'producedby pole shoes 13 and .14, produces a torque upon the armature.

This torque is opposite in direction to the force of the counteract-ingdevice 22. Rotation ot the armature under the-action of the magnetic -tield set up between the pole shoes produces rotation ofthe Vshaft by which the devices above mentioned or any other suitable .devices may be actuated.

Assuming that the air gaps are uniform, the torque I) ot' the magnet will increase at a. rate which is more than proportional to the momentary angle a, between the zero position and the intermediate positions of the armature, but theV amount of increase in the torque will become smaller with'inereasing .excitation of the lcoil unt1l the entire pole arc of the armature shoes is elnbraced by the pole shoes, and further increase of the magnetic flux by increase of the current through the coil will then be unable to cause a further increase of the torque.

It is desirable that the torque be limited to the central portion of the curve which shows the greatest increase in torque D for small variations of4 the angle a. The curve may be given any desired shape by making the air gaps irregular in size or by differentially proportioning the counteracting force f. Suitable selection of the air'gap sizes and the counteracting force will produce any desired curve or even a straight line. The torque D equals the product of the force and the angle a.

The counteracting force may be entirely omitted, as shown in Fig. '5, which is similar to Fig. .1 with the exception that the counteracting force 22 of Fig. 1 is suppliedby a structure similar to the magnet structure in Fig. 1. This modified form of the invention comprises a cylindrical housing l0 enclosed by annular end plates 12. The housing is divided into two portions I and II by means of an insulating central portion 23, which is supported by central division plates 24, which are annular in form. Each portion I and II of the housing 10.contains an excitingcoil 11 and' a plurality of pole shoes 13, '14 15 and 16, arranged in pairs as above described,

.with relation to the embodiment of the n-l vention shown in Fig. 1. The operation of each portion of the modification is exactly similar to the operation of the first-mentioned embodiment of the invention with the exception that one of the coils 11 is so wound vthat either the sum, the difference, the prod- -bution line. lVhen the above arrangement of magnetic forces is made, the turning magnet may be used .for the selectlve protection of such distrlbutlon systems. .Itw1ll be noted that they armature pole shoes 19 and 20 and 25 and 26 are symmetrically arranged with `respect to their intermediate positions, in

order that the tol-ques ofthe two magnet coils may be made exactly equal and, if necessary, opposite in direction to provide for a neutralizing action, if excitation of the coils is equal.

Fig. 6 shows the armature shoes 19, 20 and 25. 26 arranged on the shaft at angles of 90. lVith this arrangement, it is possible to utilize the invention as an indicating device in A. U. circuits, which will turn to either side whenever a certain limiting impedance is reached or exceeded. l

Although only two embodiments of the invention have'been illustrated, it will be clear to persons skilled in the art that various modilicati ons may be made therein without departing from the spirit thereof or from the scope of the appended claims.

I claim:

1. In an electro-magnet of the character described, a magnetizing coil, a plurality of pole pieces forming a core for sald coil, said pole pieces being arranged in spaced pairs, and a rotatable armature within said pole pieces, said pole pieces and said armature being spaced 'to secure a varying torque relative to the changing angular position of said armature from the normal position thereof.

2. In an electro-magnet of the character describedI` a magnetizing coil, a plurality of pole pieces forming a core for sald coil, said pole Vpieces being arranged in opposing spaced pairs, and a rotatable armature Within said pole pieces, said pole pieces being spaced for varying the torque on said armature proportionally to the change of angular position thereof relative to the normal non-operating position.

3. In an electro-magnet of the character described, a magnetizing coil, a plurality of pole pieces forming a core for said coil, said pole pieces being arranged in spaced pairs,

and a rotatable armature including armature shoes longer and narrower than the space between the pairs of said pole pieces for magnetically bridging therebetween, said pole pieces being spaced from said armature shoes to provide for varying the torque relative to the change of position thereof.

4. In an. electro-magnet of the character described, a magnetizing coil, a plurality of pole pieces forming a core for said coil, said pieces being arranged in spaced pairs, a rotatable armature for magnetically bridging the space betweensaid pairs of pole pieces, and means for counter-acting the rotating action of the magnetic field produced by said coil in said armature.

5. In an electro-magnet of the character described, a first magnetizing coil, a plurality of pole pieces forming a core for said irst coil, a'second magnetizing coil arranged adjacent said first coil, a plurality of pole pieces for said second coil, and a rotatable armature -for magnetically bridging the space between said pole shoes of said coils. l

6. In an electro-magnet of the character described, a cylindrical housing, cylindrical magnetizing coils within said housing, end plates for .enclosing said coil within said housing, said housing and said end plates 3 forming a portion of a magnetic circuit,

pairs of pole pieces for each of said coils arranged in abutting relation with said ena plates andsaid coils, and an armature for magnetically connecting said pole pieces and completing the magnetic circuit.

7. In an electro-magnet of the character described, a housing, coils within said housing, pole pieces for each ofv said coils arranged in spaced pairs, and a rotatable 40 armature magnetically connecting said pairs of pole pieces and responsive to varying magnetic ux in said coils relative to the angle of rotation thereof. j

8. In electromagnetic apparatus of the character described, an, armature, pole pieces, said pole pieces and said armature being supported `for relative movement with respect to each other about a given axis with the pole pieces spaced with respect to each 5e other in the direction of such axis and disposed respectively adjacent the end portions of said armature. v

In testimony whereof I have hereunto subscribed my name this 11th day of August,

JOSEF STOECKLIN. 

